We propose to design, implement, and evaluate for effectiveness and efficiency a preventive intervention to reduce risk-taking behaviors of inner-city minority adolescents and adults at high risk for HIV infection. Subjects will be seronegative men and women accessed through two existing community sites, the Johns Hopkins Emergency Department and the Baltimore City Health Department Eastern Health District clinics, supplemented by community outreach to residents who do not use these clinics. This diverse population is difficult to reach through other channels and is thought to require intensive approaches for changing risk-taking behaviors. The primary preventive intervention strategy proposed here will consist of small, peer-led support group sessions meeting over a 6- week period in which problem solving and decision making skills are promoted that are hypothesized to lead to reduction in risk-taking behaviors involving sexual (primarily heterosexual, in this population) practices and drug use behaviors. The overall project will be conducted in three phases. In Phase I, the approach of the overall collaborative study will be determined, focus groups of members of the study population will be convened, pilot test procedures and instruments will be developed, staff will be recruited and trained, and the statistical database will be planned. In Phase II, a total of 740 high risk subjects will be recruited and the small group intervention and evaluation instruments will be pilot tested, altered and conducted again. In Phase III, the intervention will be fully implemented and evaluated using a randomized trial in the two sites, in which a total of 1,500 subjects will be randomized into two treatment groups and one control group. The effectiveness of the intervention will be assessed through 12-month followup of subjects in which behavior chnage, incident STDs, and HIV-1 seroconversion will be measured. In addition, a process evaluation will provide dataon such issues as recruitment, attrition, and effectiveness of peer leaders that will aid in the transfer of the intervention of other sites.